Heatmap tracker is 100% accurate in terms of logging the exact mouse coordinate data which is provided by the browser.

However, dynamic content is an issue for any heatmap tool. Javascript on the site which changes layouts (such as responsive themes) can also change how a page looks at different screen widths / heights (or x/y coordinates). While we make every effort to emulate the exact environment, there's no way to be perfectly accurate across all browsers, environments and all website designs.

This is why we provide visitor recordings as well, as the recordings emulate the exact environment of your visitor. Heatmaps when used in conjunction with these recordings will give you an extremely accurate idea of how your users interact with your website.